As part of a file-sharing investigation, in 2010 authorities tracked an IP address to a house in Sweden. After a night playing video games a blurry-eyed house sitter answered the early morning call only to be welcomed by the police. They weren't looking for him, but the owner who was abroad. Sometimes, however, you can be in the wrong place at the wrong time.

For years now, particularly in light of increased monitoring of file-sharing networks, subsequent lawsuits and pay-up-or-else schemes, one particular argument has persistently raised its head.

That argument is simple, although some like to make it more complex than it is. In a file-sharing context, an IP address does not identify a person, at best it merely identifies an Internet connection. Nevertheless, countless Internet subscribers have been accused of infringements they have not committed, merely because their name is on the bill.

However, a developing case in Sweden shows that while tracking down the subscriber behind an IP address, it’s also possible to arrest and prosecute someone completely different.

In December last year a guy identified only as ‘Martin’ answered a ringing doorbell. Having played video games all night he was half asleep, arriving at the door wrapped in a blanket. Three people were outside and one of them was showing his police badge.

“At first I thought something had happened, but pretty soon they explained that it was about file sharing,” Martin told Swedish news outlet NVP.

But the police weren’t there for Martin, they were looking for the bill payer. However, he was abroad and Martin was there just as a house sitter, watering plants and feeding fish.

With the police presence expanding to five officers, network cables were disconnected, hard drives and computers seized. Despite having no initial interest in Martin, one of the computers they decided to seize was his.

Then a few weeks ago Martin was summoned to a interview with the police. There he discovered that an inspection of his computer had revealed 200 downloaded movies and he was now being pursued for illegal file-sharing.

The prosecutor in the case, Frederick Ingblad, who is also deeply involved in most of Sweden’s other file-sharing cases, admitted that they were originally looking for someone else, but Martin just happened to be in the wrong place at the wrong time.

“It is now suspected that he downloaded and uploaded particular films,” Ingblad explained.

Both individuals now stand accused of copyright infringement and their indictments are expected in the summer.

“My friends think that I had bad luck. I hardly know anyone who does not share files, since you have always been able to get what you want,” Martin said.